Method of making tubing



Oct. 16, 1945. w. D. BLATZ METHOD OF MAKING TUBING Filed April 24; 1942 {izvenivr WARREN D. BLATZ Q 7225 aiiarney ness of the plies.

'ameter causing a reduction in Patented Oct. 16, 1945 METHOD OF MAKING TUBING Warren D. Blatz, Bridgeport, Conn, assignor to The Bead Chain Manufacturing Company, Bridgeport, Conn., a corporation of Connecticut Application April 24, 1942, Serial No. 440,393 v i 8 Claims.

This invention relates to the manufacture of tubing and more particularly to the manufacture of tubing formed from one or more strips of stock of indefinite length and it is an object of this invention to provide an improved method of manufacturing tubing of the class described which is efllcient in operation and produces tubing of improvedconstruction particularly when used in forming multi-ply or laminated tubing from a plurality of strips. It is also an object of this invention to provide improved tubing of the class described.

Previously, tubing of the type described has been made by forming or shaping the strips by means of rolls and the tubing was then drawn through circular dies to reduce the tubing to the desired diameter and where a plurality of plies were'used, to bring the plies into tight engagement. However, variations in the temper or tensile strength of the strips caused variations in the elongation of they plies during the drawing operation and resulting variations *1 the thickcession particularly where the strips are of a material of low tensile strength.

In manufacturing tubing inaccordance with Such variations in the thickthis invention, a strip or strips of suitable materialare formed to tubular shape by circular forming dies. Wher a multi-ply tube is to be formed, a tube is first Iormed of a single strip and then the other strip or strips are individually and successivelyformed about that tube until a tube of the desired number of plies is secured. The tube thus formed is then swaged to the desired dithe diameters of all the plies of the tube and a thickening of each ply as well as insuring a tight engagement throughout the adjacent plies. The plies of the tube, when shaped by the circular forming dies, tend to return partly to the flat condition of the original strip or strips but, after swaging, tend to retain the tubular shape and size given by the swaging so that it is not necessary to subject the tubing to pressure during the subsequent brazing or sealing operation in order to retain the plies engaged or the tubing of the proper dimension.

In the drawing in which there is shown mechamm for the making of tubing of at. plies in accordance with this invention- Figure 1 is a fragmentary perspectlve drawing,

partly broken away, showing such parts of a machine as are necessary to illustrate the manufacture of tubing in accordance with this invention;

Figures 2, 3 and 4 are sectional views of the tubing in various stages of its manufacture, the views being. taken as on the lines 2-2, 3-3 and 4-4, respectively, of Figure 1, and

Figure 5 is a vertical longitudinal sectional view of tubing of modified form constructed in accordance with this invention.

The machine parts shown in the drawing comprise a base 24 having a groove or channel 24a in which is mounted a slide 23 adapted to be re- 'ciprocated by suitable operating means (not .bar IB is a member I5 which extends to suitable operating means (not shown) adapted to reciprocate the member l5 and thus oscillate the drawing dies I4 and l3.v

The base 24 also supports a holder I In for a swaging die II which cooperates with a corresponding die I0 mounted on a reciprocating carrier I2 which is operated by suitable means (not shown). Means for operating the slide 23 and the dies l0, I3 and HI have not been shown as means for operating such slides and dies are shown in the patent to Goodridge and Gagnon No. 1,087,876], issued February '17, 1914. Reels 2| and 22 mounted on a. suitable bracket 25 supply strips 20 and I9, respectively, of suitable material, preferably met'alffor forming the tubing.

In the manufacture of tubing, the strip stock 19 from the reel 22 is drawn through the formingdie 14 to form a tube, as l8, while the strip'stock 20 from the reel 2|: is drawn through the forming die I3 to form a tube as H, around the tube l8, the dies l4 and I3 being shown arranged so that the seams in the plies are approximately degrees apart although other spacing of the seams may be used. The tubing is then passed between the swaging dies H and I0 and swaged, in a plurality of steps as at lid and ill), to the desired outside diameter. The dies l6 and i3 form the tubes l8 and I! with the edges of the strips abut time, as shown in Figures 2 and 3, substantially cylindrical.

throughout. Although the die it forms the outer ply as closely as possible about the inner ply without causing excessive reduction of the thickness of the plies or the diameters of the tubes some voids or spaces between the. plies remain. 1

The swaging operation causes the edges of the strips forming the plies to tightly abut throughout, as shown in Figure 4, thickens the walls of the plies slightly and eliminates substantially all 1 the slide 23 is operated to draw the dies i4 and I3 outwardly or away from the dies Ill and ii and thus form addit onal portions of tubing from the'strips I! and 20. Upon completion of the outward movement of the dies l4 and IS the die It is withdrawn from the die I I and operated for the next swaging stroke. During this period the slide 2;! is moved inwardly or towards the dies l and H and during this inward movement the friction of the strips in the dies I4 and i 3 causes the tubing to be advanced between the dies it and II and additional stock to be drawn from the reels 22 and 2|. The extent of the movement of the slide 23 is just sufficient to advancethe tubing between the dies I0 and --H from one swaging position or step to the next. During one movement of the tubing inwardly towards the dies ll and II the rod i5 is operated to rotate the dies I4 and I 3 through approximately 90 degrees in one direction and during the next inward movement ofthe tubing the dies I4 and "are rotated through approximately 90 degrees in the opposite direction. These oscillating movements oi" the dies It and is are repeated upon successive inward movements of the tubing in order to insure the swaged tubing being The slide 28, the tubing and the dies M and I! have ceased movement or operation when the tubing is again engaged between the dies II and il in the next swaging operation and remain stationary until the swaging stroke is fully completed. Then during the ensuing dwell period of the dies l0 and ii the outward movement or the slide 2! and dies II and I 3 is again made. a

While the strip stock is shown as being fed from the reels directly to the forming dies H and it. it is to be understood that the strips can be partially formed to a tubular shape bymeans of forming rolls before being engaged by the dies ll and I3.

In Figures 1 to 4, the tubing iormed is shown as of a uniform cylindrical shape, but it is to be understood that by the use of suitable swaging dies tubing or tubular sections of varying diameter or form may be produced as the corrugated tubing 30 of Figure 5. The various steps in the A the tubing may be brazed or sealed by any usual or suitable means so as to-close the longitudinal manufacture of tubing 30 are the same as in the seams in the tube piles and secure the piles together. I

While the invention has been shown and described as in the manufacture of tubing having two plies, it is to be understood the invention is equally applicable to the manufacture oi tubing having a greater or lesser number of plies. In the manufacture of tubing of a single ply the method shown and described is found to be especially advantageous in that the swaging causes the seam to be tightly closed and to remain so during the brazing or welding thus eliminating the need for applying pressure to the tubing at that time and avoiding an imperfect product. a

What is claimed is:

1. The method of making tubing from continuous strip stock ,which comprises moving the stock longitudinally, fashioning successive portions of the stock into tubular form and subjecting successive sections of said'tube to cold section and thicken the wall of said tube sections throughout.

2. The method of making multi-ply tubing from continuous strips of stock which comprises moving the strips longitudinally, fashioning successive portions of one strip into tubular form to constitute an inner ply, fashioning successive portions of the second strip into tubular form around the first strip and cold'swaging successive sections of the concentric tubes between cooperating dies constructed and arranged to simultaneously swage an entire section of said concentric tubes into intimate contact throughout.

' 3. The method of making multi-ply. tubing from continuous strips of stock which comprises moving the strips longitudinally, fashioning successive portions of one strip into tubular form to constitute an inner ply, fashioning successive portions of the second strip around the first strip and continuous strips or stock which comprises moving the strips longitudinally step by step, fashioning successive portions of one strip into tubular iorm'to constitute an inner ply, fashioning successive portions of the second strip into tubular form around the first tube and subjecting successive sections of the concentric tubes-to cold swaging operations between cooperating dies constructed and arranged to simultaneously reduce the diameters of both tubes throughout an entire section, thicken the walls of said tubes and insure the tubes remaining closed along their longitudinal seams.

5. The method of making multi-ply tubing from continuous strips ofstock which comprises moving the strips longitudinally step-by step, fashioning successive portions oi one strip into tubular form to constitute an inner ply, fashioning successive portions or the second strip into tubular form around the first tube, subjecting successive sections of theconcentric tubes to cold swagins operations between cooperating dies constructed and arranged to simultaneously reduce the diameters of both tubes throughout an entire section 2,387,051 and relatively rotating said, tubes and swagins ing successive portions of the second strip around I the first strip during successive periods of rest of both strips, the longitudinal seams being angularly displaced-subjecting successive sections of the concentric fashioned strips during successive periods of rest of the strips to cold swaging operations between cooperating dies constructed and arranged to simultaneously reduce the diameters of the fashioned strips throughout an entire section step by step and insure theseam remaining closed and partially rotating the swaging operations thereon.

7. The method of making double ply tubing stri n between i from two continuous strips oi stock which comprises moving the strips longitudinally by repeated a uniform movements, tashionlng successive portions of one strip during successive periods of rest of the strip into tubular form toiconstitute an f inner ply, fashioning successive portions oi' the second strip around the first strip during successive periods of rest-of both strips and subjecting successive sections of the concentric fashioned strips during successive periods of rest of the strips to cold swas ns operations between coop crating dies constructed and arranged to simultaneously reduce the diameters of the fashioned strips throughout an entire section step by step and thicken said strips.

8. The method oi making multi-ply tubing from continuous strips of stock which comprises fashioning a strip into tubular form, fashioning a second strip into tubular form about said first tube and cold swaging said tubes into intimate contact throughout between cooperating dies con- 20 structed and arranged to simultaneously reduce the diameters of an entire section oi'said tubes.

w 10. 3mm. 

